Endangered and Threatened Wildlife and Plants; Proposal to List the San Xavier Talussnail as Endangered

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AC13

Endangered and Threatened Wildlife and Plants; Proposal to List

the San Xavier Talussnail as Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: The U.S. Fish and Wildlife Service (Service) proposes to list

the San Xavier talussnail (Sonorella eremita) as an endangered species

under the Endangered Species Act of 1973, as amended (Act). The San

Xavier talussnail is found only in an area of 15 by 30 meters (m) (50

by 100 feet (ft)) on private land in Pima County, Arizona. The primary

threat to the species results from its vulnerability to habitat

disturbances that would remove talus, increase interstitial soil, or

alter moisture accumulation and retention. This proposal, if made

final, would implement Federal protection provided by the Act for the

San Xavier talussnail. The Service seeks data and comments from the

public on this proposal.

DATES: Comments from all interested parties must be received by May 23,

1994. Public hearing requests must be received by May 9, 1994.

ADDRESSES: Comments and materials concerning this proposal should be

sent to the Field Supervisor, Arizona Ecological Services Field Office,

U.S. Fish and Wildlife Service, 3616 West Thomas Road, Suite 6,

Phoenix, Arizona 85019. Comments and materials received will be

available for public inspection, by appointment, during normal business

hours at the above address.

FOR FURTHER INFORMATION CONTACT: Debra T. Bills, at the above address

(602/379-4720).

SUPPLEMENTARY INFORMATION:

Background

The San Xavier talussnail (Sonorella eremita) is a land snail,

first described in 1910 by H.A. Pilsbry and L.E. Daniels (Pilsbry and

Ferriss 1915). The species has a globose shell with as many as 4.5

whorls, a white to pinkish tint, and a chestnut-brown shoulder band. It

is approximately 19 millimeters (0.7 inches) in diameter. This is the

only land snail fitting this description in the Mineral Hills area, but

its shell is very typical of desert Sonorella (Pilsbry and Ferriss

1915).

The San Xavier talussnail lives in a deep, northwestward-facing,

limestone rockslide in Pima County, Arizona. Its habitat is protected

from drying effects of the sun by outcrops of limestone and decomposed

granite to the northeast and southwest, and by the hill itself to the

southeast (Pilsbry and Ferriss 1915, Hoffman 1990). The vegetation,

slope of the hillside, and depth of the slide provide necessary

moisture conditions. This talussnail is similar to other Sonorella

species in that it feeds on fungus or decaying plant material (Hoffman

1990). The San Xavier talussnail is hermaphroditic (Morton 1968,

Hoffman 1990). After a rain, the snail will lay eggs, feed, and mate.

Fertilization and production of eggs takes several days. If the rains

are short-lived, the eggs are held until the next rain. The species

requires three or four years to mature, depending on rainfall

frequency, and has a reproductive life of four to six years, depending

on the total number of days it remains active (Hoffman 1990).

Talussnails are extremely sensitive to desiccation and

sedimentation resulting from disturbance of the talus and associated

vegetation. In general, desert snails are known to protect themselves

from drying out by crawling into deep, cool rockslides that are not

filled with soil. The limestone rock or other talus that contains

calcium carbonate is crucial to the species, as it aids in shell

deposition and neutralizes carbonic acid that is produced during

estivation (Hoffman 1990). The San Xavier talussnail is known to

estivate for up to three years and in most years is only active for

three or four days (Hoffman 1990).

The San Xavier talussnail was included as a Category 2 species in

the Service's May 22, 1984, notice of review of candidate invertebrates

(49 FR 21664) and in the January 6, 1989, animal candidate notice of

review (54 FR 554). Category 2 species are those for which the Service

has some evidence of vulnerability, but for which there is insufficient

scientific and commercial information to support proposed rules at the

time. The San Xavier talussnail was included as a Category 1 species in

the November 21, 1991, animal candidate notice of review (56 FR 58804).

Category 1 species are those for which the Service has sufficient

biological data to support proposals for listing.

Summary of Factors Affecting the Species

Section 4 of the Endangered Species Act (16 U.S.C. 1531 et seq.)

and regulations (50 CFR part 424) promulgated to implement the listing

provisions of the Act set forth the procedures for adding species to

the Federal lists. A species may be determined to be an endangered or

threatened species due to one or more of the five factors described in

section 4(a)(1). These factors and their application to the San Xavier

talussnail (Sonorella eremita) are as follows:

A. The present or threatened destruction, modification, or

curtailment of its habitat or range. The San Xavier talussnail is a

very restricted endemic and is extremely vulnerable to any disturbance

that would remove talus, increase interstitial sedimentation, or

otherwise alter moisture conditions in its habitat (e.g., road or trail

expansion or alteration, mining exploration) (Hoffman 1990). Within the

species' habitat are inactive mining prospects and mines, mining

stakes, a powerline across the east ridge, and a road leading to a

microwave site on the hilltop. A large copper mine is located nearby.

There are housing developments of small acreage to the north and to the

southwest of the hill. The habitat is too steep (30 to 40 percent

slope) to permit house construction, but possible future threats

include additional road construction, expansion of the copper mine and/

or tailings, and small-scale prospecting and mining.

B. Overutilization for commercial, recreational, scientific, or

educational purposes. The extremely restricted habitat of this species

makes it vulnerable to excessive collecting during periods when the

snails are active.

C. Disease or predation. No diseases are known. Rodent predation is

random and sporadic on the San Xavier talussnail (Hoffman 1990).

D. The inadequacy of existing regulatory mechanisms. The State of

Arizona offers no protection to this species. The Act would provide

protection and encourage active management through ``Available

Conservation Measures'' discussed below.

E. Other natural or manmade factors affecting its continued

existence. The very restricted range of the San Xavier talussnail makes

it vulnerable to extinction from relatively small-scale human actions.

The only known habitat for the species is on a single rockslide near

Tucson, Arizona, in an area of limestone talus about 15 by 30 m (50 by

100 ft) near a dirt road. The habitat is located downslope from a dirt

road, making it vulnerable to infiltration of rocks and soil or other

material. The species is so restricted in range that it is threatened

by even limited removal of cover through vandalism or by individuals

curious about the presence of a rare species. Removal of cover,

including both rocks and vegetation, harms snails by exposing them to

the drying effects of the sun and periods of low ambient humidity.

The Service has carefully assessed the best scientific and

commercial information available regarding the past, present, and

future threats faced by this species in determining to propose this

rule. Based on this evaluation, the preferred action is to list the San

Xavier talussnail as endangered. The species has a highly restricted

range, is located in an area of growing urban development and active

mining, and is easily accessible by road. Although the San Xavier

talussnail is on private land, Federal actions may occur as the area

continues to develop. Endangered status is most appropriate because the

single known population could be destroyed by one action. Because of

the vulnerability of the population, threatened status does not appear

appropriate for the San Xavier talussnail. A decision to take no action

would exclude this species from needed protection available under the

Act, and the species would likely decline. The decision not to propose

critical habitat for the San Xavier talussnail is explained in the

following section.

Critical Habitat

Section 4(a)(3) of the Act, as amended, requires that, to the

maximum extent prudent and determinable, the Secretary propose critical

habitat at the time a species is proposed to be endangered or

threatened. The Service finds that designation of critical habitat is

not prudent for the San Xavier talussnail at this time.

The extremely restricted habitat of the species makes it vulnerable

to collection and isolated acts of vandalism. Although there are

relatively few amateur collectors of land snails, a single collection

effort under advantageous conditions could severely deplete the

species' population. The population could, however, withstand some

limited, regulated scientific collection. Of greater concern than

collection is the potential for acts of vandalism that directly kill

the snails by crushing or by habitat disturbances that cause

desiccation of the snails. These acts may sometimes be purposeful, but

may also be caused by well-intentioned persons who are curious about

the presence of an endangered species. The likelihood of these

potential threats occurring would be greatly increased by designation

of critical habitat, because the publication of critical habitat maps

and descriptions would allow unauthorized persons to precisely identify

the locality of this species. Identification of critical habitat would

therefore increase the degree of threat to this species.

Critical habitat designation would also not provide additional

benefit to the species. The range and major ecological requirements of

this species are sufficiently known to provide adequate protection

through the Act's take prohibitions and application of the section 7

jeopardy standard. The Service will continue to communicate the

conservation needs of the species to the involved landowner, as well as

inform the landowner of the status of legal protection and conservation

planning for the species.

Available Conservation Measures

Conservation measures provided to species listed as endangered or

threatened under the Act include recognition, recovery actions,

requirements for Federal protection, and prohibitions against certain

practices. Recognition through listing encourages and results in

conservation actions by Federal, State, and private agencies, groups,

and individuals. The Act provides for possible land acquisition and

cooperation with the States and requires that recovery actions be

carried out for all listed species. The protection required of Federal

agencies and the prohibitions against taking and harm are discussed, in

part, below.

Section 7(a) of the Act, as amended, requires Federal agencies to

evaluate their actions with respect to any species that is proposed or

listed as endangered or threatened and with respect to its critical

habitat, if any is being designated. Regulations implementing this

interagency cooperation provision of the Act are codified at 50 CFR

part 402. Section 7(a)(4) requires Federal agencies to confer with the

Service on any action that is likely to jeopardize the continued

existence of a species proposed for listing or result in destruction or

adverse modification of proposed critical habitat. If a species is

listed subsequently, section 7(a)(2) requires Federal agencies to

ensure that activities they authorize, fund, or carry out are not

likely to jeopardize the continued existence of such a species or to

destroy or adversely modify its critical habitat. If a Federal action

may affect a listed species or its critical habitat, the responsible

Federal agency must enter into formal consultation with the Service.

Potential Federal activities that may require consultation under

section 7 include permits for road and transmission facilities near the

locality of the San Xavier talussnail.

The Act and implementing regulations found at 50 CFR 17.21 set

forth a series of general prohibitions and exceptions that apply to all

endangered wildlife. These prohibitions, in part, make it illegal for

any person subject to the jurisdiction of the United States to take

(includes harass, harm, pursue, hunt, shoot, wound, kill, trap,

capture, or collect; or to attempt any of these), import or export,

ship in interstate commerce in the course of commercial activity, or

sell or offer for sale in interstate or foreign commerce any listed

species. It also is illegal to possess, sell, deliver, carry,

transport, or ship any such wildlife that has been taken illegally.

Certain exceptions apply to agents of the Service and State

conservation agencies.

Permits may be issued to carry out otherwise prohibited activities

involving endangered wildlife species under certain circumstances.

Regulations governing permits are codified at 50 CFR 17.22. Such

permits are available for scientific purposes, to enhance the

propagation or survival of the species, and/or for incidental take in

the course of otherwise lawful activities.

Requests for copies of the regulations regarding listed wildlife

and inquiries regarding prohibitions and permits may be addressed to

the Office of Management Authority, U.S. Fish and Wildlife Service,

room 420C, 4401 N. Fairfax Drive, Arlington, Virginia 22203 (703/358-

2104; FAX 703/358-2281).

Public Comments Solicited

The Service intends that any final action resulting from this

proposal will be as accurate and as effective as possible. Therefore,

comments or suggestions from the public, other concerned governmental

agencies, the scientific community, industry, or any other interested

party concerning this proposed rule are hereby solicited. Comments

particularly are sought concerning:

(1) Biological, commercial trade, or other relevant data concerning

any threat (or lack thereof) to the San Xavier talussnail;

(2) The location of any additional populations of this species and

the reasons why any habitat should or should not be determined to be

critical habitat as provided by section 4 of the Act;

(3) Additional information concerning the range, distribution, and

population size of this species; and

(4) Current or planned activities in the subject area and their

possible impacts on this species.

Final promulgation of the regulation on this species will take into

consideration the comments and any additional information received by

the Service, and such communications may lead to a final regulation

that differs from this proposal.

The Endangered Species Act provides for one or more public hearings

on this proposal, if requested. Requests must be received within 45

days of the date of publication of the proposal in the Federal

Register. Such requests must be made in writing and addressed to

Arizona Ecological Services Office (see ADDRESSES section).

National Environmental Policy Act

The Fish and Wildlife Service has determined that Environmental

Assessments and Environmental Impact Statements, as defined under the

authority of the National Environmental Policy Act of 1969, need not be

prepared in connection with regulations adopted pursuant to section

4(a) of the Endangered Species Act of 1973, as amended. A notice

outlining the Service's reasons for this determination was published in

the Federal Register on October 25, 1983 (48 FR 49244).

References Cited

Hoffman, J.E. 1990. Status survey of seven land snails in the

Mineral Hills and the Pinaleno Mountains, Arizona. Prepared for U.S.

Fish and Wildlife Service, Phoenix, Arizona. Contract Number: 20181-

88-00973.

Morton, J.E. 1968. Molluscs. Hutchinson University Library. London.

244 pp.

Pilsbry, H.A., and J.A. Ferriss. 1915. Mollusca of the southwestern

states. VII. The Dragoon, Mule, Santa Rita, Baboquivari and Tucson

ranges, Arizona. Proc. Acad. Nat. Sci. Phila. 67:363-418; Plates 8-

15.

Authors

The primary authors of this proposed rule are Debra T. Bills,

Arizona Ecological Services Field Office (see ADDRESSES section),

and Dr. Steven M. Chambers, Division of Endangered Species, U.S.

Fish and Wildlife Service, P.O. Box 1306, Albuquerque, New Mexico

87123 (505/766-3972).

List of Subjects in 50 CFR Part 17

Endangered and threatened species, Exports, Imports, Reporting and

recordkeeping requirements, and Transportation.

Proposed Regulation Promulgation

Accordingly, the Service hereby proposes to amend part 17,

subchapter B of chapter I, title 50 of the Code of Federal Regulations,

as set forth below:

PART 17--[AMENDED]

1. The authority citation for part 17 continues to read as follows:

Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C.

4201-4245; Pub. L. 99-625, 100 Stat. 3500; unless otherwise noted.

2. Section 17.11(h) is amended by adding the following, in

alphabetical order under ``SNAILS,'' to the List of Endangered and

Threatened Wildlife to read as follows:

Sec. 17.11 Endangered and threatened wildlife.

* * * * *

(h) * * *

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Species Vertebrate

---------------------------------- population

where When listed Critical Special

Scientific name Historic range endangered Status habitat rules

Common name or

threatened

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* * * * * * *

Snails

* * * * * * *

Talussnail, San Sonorella U.S.A. (AZ).... NA E ........... NA NA

Xavier. eremita.

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Dated: March 14, 1994.

Mollie H. Beattie,

Director, Fish and Wildlife Service.

[FR Doc. 94-6791 Filed 3-22-94; 8:45 am]

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